Marans and barred rocks. Pics added.

I bought the rainbow package from mcmurray and the pullets are 10 weeks old. I have quite a few barred rocks and then one quite petite pullet with slightly different markings that I had originally thought was a barred rock. Her head is dark dark gray along with her tail feathers. Her barring is more black and dark gray rather than the typical slivery/white of barred rocks and is sort of blurred. Could this be a maran? I have no experience with that breed.

To be honest with you, McMurray's "Rainbow Assortment" is anything but that. In 90% of all cases I see of people asking about their chicks from the assortment, one is lucky to have an Easter Egger, and never has a Marans. . . So, they just are left with brown and white eggs. Some rainbow. And if McMurray meant a rainbow of chickens,well, they don't offer much of a rainbow. Just standard, common breeds. Sorry for the raint.